NASA SLIDES From the NASA Jet Propulsion Laboratory COMPUTER GRAPHICS - JPL1_: 1 Jupiter and Lo (volcanoes to scale) 2 Lo minus 3 hours Voyager 1 and Dipper 3 Shortly before Voyager 1 & Titan flyby 4 Voyager 1 at Saturn closest approach 5 Voyager 1 crosses Saturn ring plane 6 Voyager 2 arcs through the Saturn system 7 Voyager 2 at Saturn minus 3 hours 8 Voyager 2 at Saturn closest approach 9 Voyager 2 just before ring crossing 10 Voyager 2 just after ring crossing 11 Voyager 2 leaves Saturn for Uranus 12 Hugh crater on Mimas 13 Flying over Cassini's division 14 Using Uranus gravity assist to head for Neptune 15 Voyager 2 at Uranus encounter minus 2 hours 16 Uranus and Miranda, innermost of 5 known moons 17 Voyager 2 at Uranus closest approach 18 Diving over Neptune 7,500 km from cloud deck 19 Looking back at sun Neptune closest approach 20 Neptune & Triton 7 hrs. after Voyager 2 encounter Page 2. MANNED SPACE FLIGHTS - JPL2_: This selection of slides represents the era of the Mercury, Gemini, Apollo and Skylab missions (1960 through the mid-seventies). 1 Atlas liftoff 2 Astronaut Al White, first American space walk 3 Gemini 7 capsule in space 4 Gemini recovery 5 Capsule interior 6 Soyuz spacecraft before docking 7 Leonov - Slayton - Stafford 8 Apollo craft before docking 9 Apollo 11 liftoff 10 Apollo 10 command capsule above Moon horizon, 375 miles away 11 Apollo 9 LEM-3 above the Atlantic 12 Apollo 10: the Snoopy ascends from the Moon to dock with Charlie Brown 13 Apollo 11: Aldrin about to touch lunar surface 14 Apollo 17: Cernan walks toward rover 15 Apollo 17: Schmitt works scoop 16 Apollo 12 Astronaut Alan F. Bean visits JPL's Surveyor III 17 Apollo 9 recovery in the Atlantic 18 Skylab 3 over Earth 19 Skylab 2: Lousma flying in jet chair 20 Astronaut Garriott outside Skylab 2 Page 3. SPACE SHUTTLE MISSIONS - JPL3_: This selection of slides depicts the Space Transportation System (STS), popularly known as the Space Shuttle. Included in this slide set are the early drop-tests (1977) of the non-orbital test model Enterprise 1 747/Shuttle in Mate-Demate Device 2 Takeoff 3 Moment of parting 4 Craft, Moment after parting 5 Closeup, Enterprise landing 6 Shuttle at Launch Complex 39, night 7 Launch, Columbia's first flight 8 Solid Rocket Booster separates 9 John Young at the controls of Columbia 10 Crippen, Zero-G 11 Columbia 2 Cargo Bay 12 Columbia's approach for landing 13 Shuttle landing 14 Test fire of Columbia's maneuvering system 15 Astronauts Musgrave and Peterson float in cargo bay 16 Astronaut Musgrave and cargo bay 17 TDRS satellite deployment 18 Separation between the TDRS and the Challenger 19 Satellite view of orbiter 20 Satellite view of orbiter Page 4. EARTH - JPL4_: This is a selection of the best photographs of our planet Earth. The photographs were taken by Gemini, Apollo, Skylab, Shuttle and Landsat. 1 Earth: Antarctica (Bottom), African Continent with East Coast of Island of Madagascar (Center) 2 Himalaya Mountains 3 Northern Gulf of California 4 Los Angeles 5 Earth: Antarctica (Bottom), African Continent, Saudi Peninsula (Top Center) 6 Earth 7 Southern California, Salton Sea 8 Nile River Delta 9 Southern California, Baja, from Apollo 16 10 High Sierra from 225 miles 11 Earth 12 Gulf of Mexico 13 Earth and Mediterranean 14 U.S. East Coast 15 Great cyclonic storm 16 Earthrise over Moon 17 Earthrise over Moon 18 Earthrise over Moon 19 Earth eclipse 20 Earthrise over Moon Page 5. NASA JPL/CALTECH FACILITIES - JPL5_: Jet Propulsion Laboratory - JPL is an operating division of the California Institute of Technology and uses facilities provided by the National Aeronautics and Space Administration. JPL employs more than 4,000 people at facilities located on 175 acres northwest of Pasadena. Mission Test and Imaging System (MTIS) - MTIS is a JPL control center where planetary spacecraft radio signals, which have traveled across hundreds of million miles of space, are converted into pictures by special processing equipment. Deep Space Network - The Space Flight Operations Facility (SFOF) is the center of a worldwide communications network known as the Deep Space Network (DSN), which communicates 24 hours a day with several unmanned spacecraft traveling on their journeys through our solar system. Data is received from and transmitted to 3 tracking stations located in Madrid, Spain; Tidbinbilla, Australia; and Goldstone, California. There are three antennas at each station (26-m, 34-m and 64-m antennas). Edwards Test Station - Edwards Test Station is located at Edwards Air Force Base (near Palmdale), California. It is an off-site JPL facility used to carry out test operations that cannot easily be accommodated at JPL's Pasadena facilities. It was established in 1945 and has expanded from 35 acres to the present 600 acres. Table Mountain Observatory - Table Mountain Observatory at Wrightwood, California, is owned by NASA and operated under contract by the California Institute of Technology. The observatory was founded to perform planetary patrol work, and now has the following instruments: 1) a 16-inch Cassegrain optical telescope owned by Harvey Mudd College, 2) a 24-inch Cassegrain optical telescope with a 40-foot planetary spectrograph and 3) two radio telescopes. In addition, a 40-inch optical telescope is being installed by Pomona College on the JPL-Table Mountain site. The telescope will be jointly operated by Pomona College and JPL. The observatory carries on studies of the Sun, planets, comets, asteroids and other astronomical objects. The observatory is staffed by two JPL employees--a resident manager and a resident astronomer-and six contractor employees. It is used primarily by JPL, NASA and university and NASA-contractor astronomers. California Institute of Technology (Caltech) - Caltech began as a local school of arts and crafts founded in 1891 by the Honorable Amos G. Throop. It was known as Throop Institute until 1921, when it was transformed from an arts and crafts college into an institution of engineering and scientific research under the guidance of astronomer George Ellery Hale, chemist Arthur A. Noyes and physicist Robert A. Millikan. At that time it was renamed the California Institute of Technology (Caltech). Caltech is an independent, private university located in Pasadena, California and operates JPL for NASA. Page 6. 1 JPL buildings at Arroyo Seco 2 Aerial of JPL 3 Aerial of JPL 4 MTIS 5 MTIS 6 Goldstone 210-ft antenna 7 Goldstone 210-ft antenna 8 Goldstone 85-ft antenna 9 Spain 210-ft antenna 10 Spain 85-ft antenna 11 Australia 210-ft antenna 12 Australia 85-ft antenna 13 SFOF 14 SFOF 15 Edwards Test Station 16 Table Mountain 17 Table Mountain 18 Caltech 19 Caltech 20 Foothill complex Page 7. 1973-1983 PROJECTS - JPL6_: Mariner 10 - The Mariner 10 spacecraft was launched on November 3, 1973, from Kennedy Space Center in Florida. Its primary objective was to fly by and study the planets Venus and Mercury. Calculations showed that it would be possible to use the gravity of Venus to propel the spacecraft onward for an encounter with Mercury, providing a "space first" - visiting two planets with one spacecraft. Because the orbits of Mercury and the spacecraft were synchronous (Mercury orbited the Sun twice as the spacecraft orbited the Sun once) it was possible for the spacecraft to make three passes by Mercury, Mariner 10 encountered Venus on February 5, 1974 and Mercury on March 20 and September 21, 1974 and March 16, 1975. The spacecraft returned approximately 8,200 black and white photographs of Venus and Mercury. Weight of the spacecraft (including the instruments) was 1,280 lbs. The spacecraft was built by Boeing Co. Seasat - Seasat was launched on June 26, 1978, from Vandenberg Air Force Base in California. Its objective was to study the world's oceans from near-polar orbit (500 miles above the Earth), with microwave instruments. The satellite operated successfully for 105 days when a power failure ended its mission. The massive amount of data returned, however, is still being analyzed with outstanding scientific results. Seasat was built by Lockheed Missiles and Space Company and weighed 5,050 lbs. Viking - Two Viking spacecraft (each consisting of an orbiter and a lander) were launched from Kennedy Space Center in Florida. Viking 1 was launched on August 20, 1975 and Viking 2 on September 9, 1975. Their objective was to study Mars from orbit and to land two landers on the surface of Mars to study Mars' surface composition and to search for life on the planet. This was the United States' first attempt to land a spacecraft on another planet. Viking 1 went into orbit around Mars on June 19, 1976; the lander touched down on the surface at Chryse Planitia on July 20, 1976. Viking 2 went into orbit around Mars August 7, 1976; the lander touched down at Utopia Planitia on September 3, 1976. The end of mission for both orbiters was due to depletion of attitude control fuel; orbiter 2 on July 25, 1978 and orbiter 1 on August 7, 1980. End of mission for lander 1 occurred on April 11, 1980. The last transmission received from lander 2 was November 13, 1982. The orbiters were built by the Jet Propulsion Laboratory; the landers by Martin Marietta Corp. Total weight of each lander and orbiter was 7,750 lbs. The orbiters and landers returned over 56,000 black and white and color photographs of the surface of Mars. Voyager - Two Voyager spacecraft were launched in 1977 from Kennedy Space Center in Florida. Voyager 1 flew by Jupiter in March of 1979 and Saturn in November of 1980. The spacecraft is now traveling toward the edge of the solar system to study interstellar space. Voyager 2 flew by Jupiter in July of 1979 and Saturn in August of 1981. This spacecraft will fly by Uranus in January of 1986 and Neptune in August of 1989. Both voyagers are expected to exit the heliosphere (the outer edges of the solar wind) in the 1990s. Page 8. Infrared Astronomical Satellite (IRAS) - IRAS was launched from Vandenberg Air Force Base in California on January 25, 1983. Its mission was to map all infrared objects in the universe including stars, galaxies and the dark clouds of dust and gas where stars are born, from an orbit 550 miles above Earth. The IRAS mission ended on November 21, 1983, when the satellite's supply of coolant was depleted. IRAS was an international mission conducted by the United States, the Netherlands and the United Kingdom. JPL was the U.S. management center for the project and will produce the IRAS sky map and catalog of infrared sources. 1 Mariner 10 spacecraft 2 Mariner 10, Venus 3 Mariner 10, Mercury 4 Mariner 10, Mercury 5 Mariner 10, Mercury 6 Seasat 7 Seasat, L.A. Basin 8 Seasat, topographic map of ocean 9 Seasat, Southwest Pacific 10 Viking Orbiter/Lander 11 Viking Lander 12 Viking, Mangala Valles 13 Viking, Tharsis Ridge 14 Viking, Chryse Planitia 15 Viking, Trench 16 Voyager spacecraft 17 Voyager spacecraft 18 IRAS 19 Andromeda Galaxy 20 Andromeda Galaxy Page 9. HISTORICAL MISSIONS - JPL7_: First Rocket Testing - The first firing of a liquid rocket engine was done in the Arroyo Seco on October 31, 1936, near the present site of JPL in Pasadena, California. JATO - First test of Jet-Assisted Takeoff (JATO) rockets aboard an aircraft was done in 1941. They were developed by the Jet Propulsion Laboratory for the U.S. Army Corps. Explorer I - Explorer I, the first U.S. satellite, was launched into Earth orbit on January 31, 1958. Its objective was to provide preliminary information on the environment and conditions in space outside Earth's atmosphere. This satellite discovered the Van Allen Radiation Belts. It circled the Earth more than 58,000 times before re-entering the Earth's atmosphere over the South Pacific on March 31, 1970. Explorer I was built by the Army Ballistic Missile Agency and JPL and it weighed 30 lbs. Pioneer IV - Pioneer IV, JPL's first NASA project, was launched on March 3, 1959. Its objective was to measure cosmic radiation, establish the probe trajectory which was to verify the design of the tracking and communication system and to permit more accurate determination of the Moon's mass. This was the first U.S. spacecraft to escape Earth's velocity. Batteries which powered the transmitters on Pioneer IV went dead 82 hours, 4 minutes after launch. The signal was lost when Pioneer IV was 407,000 miles from Earth - a new tracking record. Built by JPL, it weighed 13 lbs. Ranger 1 - Ranger 1 was launched on August 23, 1961. Its objective was to develop and test basic elements of spacecraft technology required for lunar and interplanetary missions. IT made 111 orbits of Earth and traveled 3,000,000 miles. Built by JPL; 675 lbs. Ranger 3 - Ranger 3 was launched on January 26, 1962. This was the first attempt by the United States to take closeup pictures of the Moon and to make measurements on the lunar surface. However, Ranger 3 arrived at intercept with the Moon's orbit too early because of excess launch vehicle velocity. No photos were taken. The spacecraft flew by the Moon at a distance of 22,862 miles. The spacecraft was built by JPL and weighed 727 lbs. Ranger 7 - Ranger 7 was launched on July 28, 1964 and impacted the Moon at the Sea of Clouds on July 31, 1964. Its objective was to acquire and transmit photographs of the lunar surface before impacting the Moon. Ranger 7 was the first U.S. spacecraft to obtain close-up photographs of the Moon, transmitting 4,316 photographs of the Moon's surface to Earth. Surveyor - Seven Surveyor spacecraft were launched between June 1966 and January 1968. The objective for all missions was a lunar soft landing and to provide data in support of the Apollo program. Surveyors 1,3, 5, 6 and 7 transmitted several thousand black and white photographs of the Moon. The spacecraft were built by Hughes Aircraft Co. Weight of the Surveyors ranged from 600-637 lbs. Page 10. Mariner 2, the world's first successful interplanetary spacecraft, was launched on Aug. 27, 1962 and made its closest encounter with Venus on Dec. 14, 1962. Its objective was to fly by Venus, perform close-range infrared and microwave measurements and to collect and transmit information on interplanetary phenomena. JPL; 447 lbs. Mariner 4 was launched on November 28, 1964 and made its closest encounter with Mars on July 14, 1965 (flyby distance was 6,118 miles). Its objective was to fly by Mars and to perform scientific measurements in interplanetary space between the orbits of Earth and Mars and in the vicinity of Mars. Built by JPL, it weighed 575 lbs. Mariner 5 - Mariner 5 was launched on June 12, 1967 and made its closest encounter with Venus on October 19, 1967 (flyby distance was 2,480 miles). Its objective was to fly by Venus and obtain scientific information on the origin and nature of Venus and its environment. The spacecraft was built by JPL and weighed 540 lbs. Mariner 6 and 7 - Mariner 6 was launched on February 24, 1969 and made its closest encounter with Mars on July 30, 1969 (flyby distance was 2,131 miles). Its objective was to fly by Mars' equator to study Martian surface and atmosphere. Mariner 7 was launched on March 27, 1969 and made its closest encounter with Mars on August 5, 1969 (flyby distance was 2,130 miles). Its objective was a flyby over Mars' southern hemisphere. Both spacecraft were built by JPL and weighed 850 lbs. Mariner 6 returned 75 black and white photos of Mars and Mariner 7 returned 126. Mariner 9 - Mariner 9 was launched May 30, 1971 and encountered Mars on November 13, 1971 (orbit distance was 862 miles). Its objective was the study of Mars from orbit: Map the planet and look for sites for the Viking landers. Mariner 9 took the first pictures showing the surface of Mars' two moons, Deimos and Phobos. The spacecraft was built by JPL and weighed 2,150 lbs. Mariner 9 returned 7,329 black and white photographs of Mars and its moons. 1 First rocket testing at Arroyo Seco 2 JATO (Jet-Assisted Takeoff) 3 Explorer I spacecraft 4 Pioneer IV spacecraft 5 Ranger I spacecraft 6 Ranger 3 spacecraft 7 Ranger 7 spacecraft 8 Ranger 9, Lunar Crater Alphonsus 9 Surveyor spacecraft 10 Surveyor, Lunar landscape north of Crater Tycho 11 Mariner 2 spacecraft 12 Mariner 4 spacecraft 13 Mariner 4, Mars (Atlantis) 14 Mariner 5 spacecraft 15 Mariner 6 and 7 spacecraft 16 Mariner 6, 15 degrees below equator at Meridiani Sinus 17 Mariner 7, mosaic, South Polar cap of Mars 18 Mariner 9 spacecraft 19 Mariner 9, Mars channel 20 Mariner 9, Nix Olympica Page 11. VOYAGER MISSION TO JUPITER - JPL8_: Two Voyager spacecraft were launched in 1977 from Kennedy Space Center in Florida. Voyager 1 flew by Jupiter in March of 1979 and Saturn in November of 1980. The spacecraft is now traveling toward the edge of the solar system to study interstellar space. Voyager 2 flew by Jupiter in July of 1979 and Saturn in August of 1981. This spacecraft will fly by Uranus in January of 1986 and Neptune in August of 1989. Both voyagers are expected to exit the heliosphere (the outer edges of the solar wind) in the 1990s. 1 Voyager spacecraft 2 Liftoff 3 Jupiter with moons Io (left), Europa (below Jupiter), Ganymede (lower left), Callisto (lower right) 4 Jupiter's Great Red Spot at extreme right, 23.3 million miles 5 Jupiter and 2 of its moons - Ganymede (R. Center) and Europa (Top R.) taken from 29 million miles 6 Jupiter from equator to southern polar latitudes close to Great Red Spot 7 Jupiter's ring illuminated by sunlight coming from behind the planet 8 Closeup of Jupiter's cloud movement 9 Color composite of Jovian atmosphere taken 6.4 million miles from Jupiter 10 Closeup of cloud movement in Northern Hemisphere 11 Ganymede from 1.2 million kilometers 12 Ganymede from 151,800 miles 13 Europa, smallest moon of Jupiter, 1.2 million miles 14 Closeup of Europa from 150,000 miles 15 Callisto taken from 1,438,000 miles 16 Photomosaic of Callisto is composed of 9 frames taken from 245,000 miles 17 False color computer mosaic of Io 18 Io, massive volcano at horizon, Debris to height of 100 miles 19 Io from 77,100 miles 20 Tiny, red Amalthea, Jupiter's innermost satellite, 225,000 miles Page 12. VIKING MISSION TO MARS - JPL9_: Two Viking spacecraft (each consisting of an orbiter and a lander) were launched from Kennedy Space Center in Florida. Viking 1 was launched on August 20, 1975 and Viking 2 on September 9, 1975. Their objective was to study Mars from orbit and to land two landers on the surface of Mars to study Mars' surface composition and to search for life on the planet. This was the Unites States' first attempt to land a spacecraft on another planet. Viking 1 went into orbit around Mars on June 19, 1976; the lander touched down on the surface at Chryse Planitia on July 20, 1976. Viking 2 went into orbit around Mars August 7, 1976; the lander touched down at Utopia Planitia on September 3, 1976. The end of mission for both orbiters was due to depletion of attitude control fuel; orbiter 2 on July 25, 1978 and orbiter 1 on August 7, 1980. End of mission for lander 1 occurred on April 11, 1989. The last transmission received from lander 2 was November 13, 1982. The orbiters were built by the Jet Propulsion Laboratory; the landers by Martin Marietta Corp. Total weight of each lander and orbiter was 7,750 lbs. The orbiters and landers returned over 56,000 black and white and color photographs of the surface of Mars. 1 Ground-based telescope photo of Mars by Dr. Robert Leighton 2 Viking lander 3 Liftoff 4 Mars approach 5 Olympus Mons (great volcano) 6 Closeup of Phobos (moon of Mars) 7 Great Ice Cliffs, North Polar Region 8 Huge Martian canyon, Valles Marineris 9 First photo of Mars' surface, Viking I 10 First color photo, Viking I 11 Valles Marineris, Viking I 12 Soil sampler with completed trench, Viking I 13 Viking II and Martian Utopian Plain 14 Valles Marineris, Viking I 15 Utopian Plain, Viking II 16 Tharsis Ridge, youngest volcanic region on Mars 17 Computer image and data screen 18 Sand Dunes, Chryse Planitia Basin, Viking I 19 Utopian Plain, Viking II 20 Martian sunset, Viking I Page 13. MARINER 9 MISSION - JPL10_: Mariner 9 was launched May 30, 1971 and encountered Mars on November 13, 1971 (orbit distance was 862 miles). Its objective was the study of Mars from orbit; map the planet and look for sites for the Viking landers. Mariner 9 took the first pictures showing the surface of Mars' two moon. Deimos and Phobos. The spacecraft was built by JPL and weighed 2,150 lbs. Mariner 9 returned 7,329 black and white photographs of Mars and its moons. 1 Mariner 9 spacecraft 2 View of Mars from Mariner 7 spacecraft 3 Valles Marineris 4 Western region of Valles Marineris 5 Martian canyon near Tithonius Lacus 6 Frost-rimmed crater 7 Transecting ridges 8 Volcanic mountain, Nix Olympica 9 Shadow of moon Phobos on Mars' surface 10 Phobos, moon of Mars 11 Nix Olympica region 12 Chaotic terrain 13 Sinuous valley in the Rasena region 14 Crater near Pavonis Lacus 15 Novus Mons area 16 Mountain near Nodus Gordii 17 Sinuous valley 18 Phoenicis Lacus area 19 Pits and hollows 500 miles from Martian South Pole caused by wind or thawing of subsurface ice 20 Martian rilles Page 14. VOYAGER MISSION TO SATURN - JPL11_: Two Voyager spacecraft were launched in 1977 from Kennedy Space Center in Florida. Voyager 1 flew by Jupiter in March of 1979 and Saturn in November of 1980. The spacecraft is now traveling toward the edge of the solar system to study interstellar space. Voyager 2 flew by Jupiter in July of 1979 and Saturn in August of 1981. This spacecraft will fly by Uranus in January of 1986 and Neptune in August of 1989. Both Voyagers are expected to exit the heliosphere (the outer edges of the solar wind) in the 1990s. 1 Montage of Saturnian system: Dione front, Tethys, Mimas right, Enceladus, Rhea left. Titan distant top. 2 Color-enhanced image of Saturn, Oct. 18, 1980. Range, 34 million km. 3 Saturn and three moons, Tethys, Dione and Rhea, Aug. 4, 1981. 13 million miles. 4 Saturn. Moons Tethys, Dione. Shadows, rings and moons on Saturn. Photo Nov. 3, 1980. Range 13 million km. 5 Saturn's Northern Hemisphere. Aug. 19, 1981. Range 4.4 million miles. 6 Enhanced image. Saturn's clouds. Photo Nov. 5, 1980. Range 9 million km. 7 Saturn rings. Color variations indicate different chemical composition. 8 Saturn C-ring and B-ring with many ringlets. False-color image. Aug. 23, 1981. 9 Saturn's rings. Photo Nov. 12, 1980. Range 717,000 km. 10 Saturn rings with "spoke" features in B-ring. Aug. 22, 1981. 2.5 million miles. 11 Wide-angle view of rings just before Voyager crossed ring plane. Shows entire ring system highly foreshortened. 12 F-ring. Two braided separate orbit rings. Photo Nov. 12, 1980. Range 750,000 km. 13 Cloud-covered Titan. Northern Hemisphere is lighter in color than Southern Hemisphere. 14 Moon Titan and thick haze. Photo Nov. 12, 1980. Range 435,000 km. 15 Saturn Moon Tethys. Note huge canyon system. 16 Moon Dione. Many impact craters. Photo Nov. 12, 1980. Range 162,000 km. 17 Moon Mimas. Heavily cratered. Photo Nov. 12, 1980. Range 129,000 km. 18 Saturn's Moon Enceladus. 310 miles in diameter. Aug. 25, 1981. 74,000 miles. 19 Enhanced image Moon Rhea. Photo Nov. 11, 1980. Distance 1.7 million km. 20 Saturn Moon Hyperion. Irregular disc-shaped body. 235 miles across. Aug. 24, 1981. Page 15. INFRARED ASTRONOMICAL SATELLITE (IRAS) - JPL12_: Infrared Astronomical Satellite (IRAS) - The mission of the Infrared Astronomical Satellite (IRAS) was to scan the entire sky in search of infrared radiation from galaxies, dust clouds, stars, solar system objects and previously unknown sources. A new map of the infrared universe will be produced from IRAS data. Earth's atmosphere absorbs much of the infrared radiation from space and is itself a strong source of radiation. Therefore, high- sensitivity infrared observations can only be made from a telescope operating above the atmosphere. The IRAS telescope was cooled to within a few degrees of absolute zero by liquid helium and scanned the sky from an orbit 900 km (500 miles) high. IRAS detected cool objects which emit the bulk of their radiation in the infrared, but so little radiation in the visible that they cannot be seen by even the most powerful optical telescope. Because infrared radiation passes freely through interstellar dust clouds, many objects that are hidden from the view of optical telescopes were clearly observed by IRAS. IRAS was launched from the NASA Western Test Range in California at 6:17 p.m. (PST) on January 25, 1983. The mission ended on November 21, 1983 when the telescope's helium was depleted. IRAS is a joint project with the United States, the United Kingdom and the Netherlands. JPL manages the project for the United States. 1 IRAS under construction at Fokker in the Netherlands 2 IRAS in the space simulator at JPL 3 IRAS being prepared for launch 4 IRAS on the Delta booster 5 Launch on January 25, 1983, 6:17 PST 6 Launch on January 25, 1983, 6:17 PST 7 Artist's rendition of IRAS in orbit over Western Europe 8 IRAS orbit characteristics 9 Large Magellanic Cloud by Schmidt Telescope, Australia 10 Part of the Large Magellanic Cloud by IRAS 11 Comet IRAS-Araki-Alcock discovered May 8, 1983 12 Protostar in Barnard 5 13 Andromeda Galaxy (M31) as seen by 200" Telescope, Palomar Observatory 14 Andromeda Galaxy (M31) by IRAS 15 Central region of the Milky Way showing Galactic Center (Palomar Observatory) 16 Central region of the Milky Way showing Galactic Center (IRAS) 17 Earth's location in our galaxy 18 Infrared cirrus clouds 19 Orion Nebulae by IRAS 20 Unidentified infrared source Page 16. HALLEY'S COMET - INTERNATIONAL ACTIVITIES - JPL13_: Halley's Comet, the most famous of all the comets, is making its closest approach to the Sun since 1910 on February 9, 1986. Astronomers around the world are preparing to study it with the most modern techniques available. Instrumentation on the ground, in aircraft and in spacecraft will be used for detailed observations of various cometary phenomena. The nucleus of Halley will receive much attention as astronomers try to determine its size, geography, rotation and composition. The atmosphere, or coma, generated as the nucleus sublimates in the warmth of the Sun will be studied to understand the complex chemistry occurring there as well as the composition of the dust released when the frozen gases (water, carbon dioxide and others) of the nucleus sublimate. The evolution and activity of the gas and dust tails will receive attention to better understand them. Recorded in history on the average every 76 years since 240 B.C. (except for the 164 B.C. appearance), this appearance of Halley's Comet is sure to provide a wealth of new knowledge about comets and perhaps the origin of the solar system. 1 Portrait of Edmond Halley. This famous British scientist made the first prediction of the return of a comet that now bears his name. (Note: Halley rhymes with valley.) 2 Representations of comets from the 16th (upper right, lower left), 19th (upper left) and early 20th (lower right) centuries. 3 Halley's orbit as seen from above the plane of the solar system. 4 Model of a cometary nucleus, source of all cometary material. 5 The principal parts of a comet. The sublimation of frozen gases in the cometary nucleus forms the coma: The action of sunlight and the solar wind draw out the dust and gas tails. 6 A comet's tail always points away from the sun but doesn't necessarily follow the head. 7 Electron micrograph of a particle believed to be part of a comet's dust tail. 8 Portion of the Bayeaux Tapestry showing Halley's comet in 1066 before the Norman Conquest of England. 9 Nuremburg Chronicle (published in 1493) representation of Halley's Comet in 684 A.D. 10 A 17th Century print of Halley's Comet over Jerusalem in 66 A.D. 11 Drawings of the inner coma in October 1835 by F.W. Bessel. 12 Lowell Observatory wide angle photograph of Comet Halley on May 13, 1910, showing the comet, a meteor superimposed on the tail, bright Venus, and the streaked lights of Flagstaff. 13 Lowell Observatory photo of Comet Halley computer processed and false color added by M.J.S. Belton, Kitt Peak National Observ. 14 The first view of Halley's Comet since 1911 shows only the starlike nucleus on October 16, 1982. 15 The worldwide International Halley Watch organization is coordinating, standardizing, and archiving the observations of astronomers working in seven disciplines around the world. 16 NASA's International Cometary Explorer spacecraft (ICE) approaching Comet Giacobini-Zinner in September 1985. 17 U.S. Naval Observatory photograph of Comet Giacobini-Zinner. 18 European Space Agency's Giotto spacecraft to study Comet Halley. 19 Intercosmos' Venera-Halley spacecraft Vega to study the comet. 20 Japan's Planet-A spacecraft to study Halley's Comet. Page 17. VOYAGER MISSION TO URANUS - JPL14_: Voyager 2 encountered distant Uranus, seventh planet from the Sun, in January 1896. At the point of closest approach, on January 24, the spacecraft flew 50,600 miles above Uranus' cloudtops. Voyager 2 returned thousands of images and voluminous amounts of other data on the planet, its system of rings and its moons. Ten moons were discovered, as were new details in the rings and the planet's atmosphere. Its cameras obtained startling images of Uranus' five previously known moons - Miranda, Ariel, Umbriel, Titania & Oberon. Since launch in 1977, it has visited Jupiter, Saturn & Uranus. 1 True-color (left) and false-color views of Uranus, January 17, 1986. Range 5.7 million miles. 2 False-color composite of Uranus shows discrete cloud. January 14, 1986. Range 8.0 million miles. 3 Time-lapse images show cloud movements in Uranus' atmosphere over 4.6 hr. interval. January 14, 1986. Range 8.0 million mi. 4 Montage simulates view over horizon of Miranda toward planet and rings 65,000 miles away. 5 Farewell shot of crescent Uranus as Voyager 2 departs. January 25, 1986. Range 600,000 miles. 6 Three of the moons discovered by Voyager 2: 1986U1, 1986U3, 1986U4. January 18, 1986. Range 4.8 million miles. 7 Two "shepherd" moons, 1986U7 and 1986U8, with epsilon ring. January 21, 1986. Range 2.5 million miles. 8 False-color composite of Uranus' rings (from top): epsilon, delta, gamma, eta, beta, alpha, 4, 5, and 6. January 21, 1986. Range 2.6 million miles. 9 Rings of Uranus, including newly discovered 10th ring designated 1986U1R (barely visible below outermost, epsilon ring). January 23, 1986. Range 690,000 miles. 10 Backlit view shows continuous distribution of fine particles throughout ring system. January 24, 1986. Range 147,000 miles. 11 Heavy cratering seen in most detailed view of Umbriel. January 24, 1986. Range 346,000 miles. 12 Best image of Oberson shows cratering and large peak on moon's lower limb. January 24, 1986. Range 410,000 miles. 13 Mosaic of Ariel, most detailed view from Voyager 2, shows numerous faults and valleys. Jan. 24, 1986. Range 80,000 mi. 14 Highest-resolution picture of Titania displays prominent fault valleys nearly 1,000 miles long. January 24, 1986. Range 229,000 miles. 15 Color composite shows evidence of impact scars and past geologic activity on Titania. January 24, 1986. Range 300,000 miles. 16 Computer mosaic of Miranda images shows varied geologic regions at high resolution. Jan. 24, 1986. Range 18,700 to 25,000 mi. 17 Unusual "chevron" figure seen on approach to Miranda. January 24, 1986. Range 26,000 miles. 18 Varied terrain on Miranda indicates complex geologic history. January 24, 1986. Range 21,000 miles. 19 Voyager 2 image of Miranda taken shortly before closest approach. January 24, 1986. Range 19,000 miles. 20 Miranda displays rugged, high-elevation terrain (right), lower, grooved terrain and large crater (lower left) 15 miles across. January 24, 1986. Range 22,000 miles. Page 18. INFRARED ASTRONOMICAL SATELLITE (IRAS) II - JPL15_: A joint mission of the United States, The Netherlands and the United Kingdom, the Infrared Astronomical Satellite (IRAS) captured a wealth of pictures of celestial objects ranging from stars and galaxies to interstellar dust and gas. The spacecraft was launched by NASA from Vandenberg Air Force Base, California, atop a Delta 3910 on January 25, 1983. Assuming a 900-kilometer-high (563-mile) polar orbit around the Earth, IRAS spent the next 10 months photographing infrared heat emissions from celestial objects with its refrigerated 22.5-inch-diameter telescope. Superfluid helium was used to cool the telescope to 2.4 degrees Kelvin (-455 degrees Fahrenheit), minimizing interference from the spacecraft's own heat. The mission ended November 21, 1983, when coolant was depleted. Data collected by IRAS are being assembled at the Jet Propulsion Laboratory/California Institute of Technology Infrared Processing and Analysis Center (IPAC) into a sky map and a catalog of more than 200,000 infrared sources. 1 Night liftoff 2 John Herschel discovers infrared by measuring Sun with prism and thermometers. 3 IRAS spacecraft in thermal/vacuum chamber 4 IRAS in orbit (artist's conception) 5 Eta-Carina Nebula, Milky Way Galaxy 6 Dust bands in zodiacal cloud, solar system ecliptic 7 Comet IRAS-Araki-Alcock 8 Point sources, entire sky 9 Sharpless 171, star formation in Milky Way 10 Supernova remnant in Cygnus constellation 11 Solar-type star forming in Barnard 5 cloud 12 All-sky image with plane of Milky Way Galaxy 13 Beta Pictoris (ground-based optical image) 14 Interstellar cirrus emission 15 Large Magellanic Cloud 16 Star formation in Orion constellation 17 Central part of Milky Way Galaxy 18 Andromeda Galaxy (optical image from Palomar Observatory,infrared from IRAS) 19 Panoramic view of Milky Way Galaxy 20 Small Magellanic Cloud Page 19. FUTURE MISSIONS - JPL16_: These are the future unmanned space exploration missions planned by NASA/JPL from now until the early part of the next century. Some missions will begin in the very near future, others have yet-to-be- funded. For all the missions JPL has either built or designed the spacecraft or has contributed key scientific instruments that will fly on the spacecraft. 1 Engineers ready the Galileo spacecraft at the Jet Propulsion Laboratory; the 6,000 pound spacecraft is scheduled to begin its journey to Jupiter in October 1989. 2 This artist's drawing shows the Galileo spacecraft as it travels through space with its high-gain antenna opened and its magnetometer sensors extended. It will use the gravity of Venus and Earth to carry it to Jupiter and arrive in late 1995. 3 The burn of the Inertial Upper Stage (IUS) rocket carries the Galileo spacecraft away from the Space Shuttle. 4 This artist's drawings shows the Galileo probe as it descends into Jupiter's stormy atmosphere to take samples of cloud layers. The probe will transmit its data to the orbiter which will send it back to Earth. 5 The Magellan spacecraft undergoes testing at Martin Marietta Astronautics in Denver. To save costs, several major pieces of Magellan's hardware are spares from other missions. 6 The Magellan spacecraft, attached to an Inertial Upper Stage (IUS) rocket, is carried into low Earth orbit by the space shuttle. Magellan will travel one and half times around the Sun before it arrives at Venus 15 months after launch. 7 This artist's drawing shows the Magellan spacecraft with its solar panels pointed toward the Sun as it begins its orbit near the north pole of Venus. 8 This artist's drawing shows the Magellan spacecraft in an elliptical orbit around Venus and illustrates the mapping and data transmission phases of the mission. 9 The Mars Observer spacecraft scans the surface of the red planet from its orbit in this artist's drawing. Mars Observer is the first mission to use the new, low-cost Observer class spacecraft. 10 The Mars Rover Sample Return (MRSR) mission will send a lander to Mars to collect soil samples for transport to Earth. The mission would be a precursor to eventual manned Mars exploration. 11 Ulysses, a joint project between NASA and the European Space Agency, will carry nine instruments to conduct experiments at polar regions of the Sun and in interstellar space never before explored. 12 In this artist's drawing, the Comet Rendezvous Asteroid Flyby (CRAF) spacecraft ejects a penetrator toward the nucleus of a comet. CRAFT is the first mission of the Mariner Mark II series of spacecraft. 13 The Cassini spacecraft arrives at Titan, Saturn's largest moon, in this artist's drawing. This Mariner Mark II spacecraft will orbit Saturn and carry a probe to sample the atmosphere of Titan. Cassini is a joint Nasa-European Space Agency project. Page 20. 14 NASA's Hubble Space Telescope will carry JPL's Wide- Field/Planetary Camera as one of its five astronomical instruments. In this drawing, a shuttle approaches the telescope so that the astronauts may perform periodic maintenance. 15 The Ocean Topography Experiment (TOPEX/Poseidon) is an international effort will be launched aboard a French Ariane rocket to study a variety of sea phenomena. 16 JPL's Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument sits in the cargo bay of the Space Shuttle and looks at Earth's atmosphere to determine its composition at various altitudes. 17 JPL's Shuttle Imaging Radar (SIR) flies in the shuttle cargo bay and has the ability to collect data over virtually any region, with no regard for weather or sunlight. 18 The NASA Scatterometer (NSCAT) will make high-resolution measurements of winds near the ocean's surfaces to determine how the sea and air interact. 19 The Earth Observing System (Eos) will carry about 10 instruments to observe the surface and atmosphere of the planet for more than a decade; it is a major element of NASA's Mission to Planet Earth. 20 The Thousand Astronomical Units (TAU) mission would be launched from the Space Station and would travel 1,000 astronomical units (93 billion miles) from the Sun in a 40 year period to broaden the baseline for astrometric measurements of the stars. Page 21. VOYAGER MISSION TO NEPTUNE - JPL17_: Two Voyager spacecraft were launched in 1977 from Kennedy Space Center in Florida. Voyager 1 flew by Jupiter in March 1979 and Saturn in November 1980. Voyager 2 flew by Jupiter in July 1979, Saturn in August 1981, Uranus in January 1986 and Neptune in August 1989. The two spacecraft are now traveling out of the solar system into interstellar space -- searching for the heliopause, or the outer boundary of the Sun's energy influence. 1 False-color image of Neptune. Red areas are semitransparent haze covering planet. 2 Neptune's Great Dark Spot, accompanied by white high-altitude clouds. 3 Cloud systems in Neptune's southern hemisphere. 4 Neptune through various camera filters. Views reveal altitude data on cloud features. 5 Great Dark Spot. This storm system rotates counterclockwise. 6 High-altitude cloud streaks in Neptune's atmosphere. 7 Two views of satellite 1989N2. Dark, irregularly shaped moon was discovered by Voyager 2. 8 Satellite 1989N1, discovered by Voyager 2. 9 Neptune's ring system, shown in two exposures lasting nearly 10 minutes each. 10 Detail of Neptune's rings. 11 Bright southern hemisphere on Triton. 12 View about 300 miles across of Triton's surface. 13 Triton from 80,000 miles. Long feature is probably a narrow down-dropped fault block. 14 Triton's south polar terrain. About 50 dark plumes mark what may be ice volcanoes. 15 Triton from 25,000 miles. Depressions may be caused by melting and collapsing of icy surface. 16 Computer-generated perspective view of one of Triton's caldera- like depressions. 17 High-resolution color mosaic of Triton. 18 Triton just after closest approach. 19 Post-encounter view of Neptune's south pole. 20 Neptune and Triton 3 days after flyby. Triton is smaller crescent and is closer to viewer. Page 22. MAGELLAN AT VENUS - JPL18_: Magellan is a NASA spacecraft mission to map the surface of Venus with imaging radar. The basic scientific instrument in a synthetic aperture radar, or SAR, which can look through the thick clouds perpetually shielding the surface of Venus. Magellan is in orbit around Venus which completes one turn around its axis in 243 Earth days. That period of time, one Venus rotation, is the length of Magellan's primary mission. During that time Magellan will map about 80% of the Venus surface. Subsequent missions of equal duration will provide complete mapping of the planet. Magellan was launched May 4, 1989, aboard the space shuttle Atlantis and went into orbit around Venus August 10, 1990. The spacecraft completes one orbit every 3 hours and 15 minutes, passing as close to the planet as 294 kilometers (183 miles) and as far away from Venus as 8,742 kilometers (5,265 miles). The smallest visible objects measure approximately 120 meters (400 feet). 1 P-36644 Trough feature, 28 km wide, 60 S, 347 E. 2 P-36698 Wind streaks and fractured plains, 40 km wide, NE of Ushas Mons. 3 P-36699 Gridded plains, 37 km wide, 30 N, 333 E. 4 P-36838 Mosaic of area between Navka and Lavinia Planitia, 475 km wide, 20 S, 337 E. 5 P-36908 Western part of Clotho Tessera, 300 km wide, 55 N, 335 E. 6 P-36909 Soviet Venera (Behepa) 8 landing site in Navka, 400 km wide, 10 S, 335 E. 7 P-37125 "Pancake" volcanic domes, average 25 km diameter, 30 S, 11.8 E. 8 P-37128 Impact crater Aurelia, 31.9 km diameter, 20.3 N, 331.8 E. 9 P-37135 Ridge belts in Lavinia Region, 615 km wide, 40 S, 342.5 E. 10 P-37137 False-color image of Sacajawea Patera Volcano, 120 km wide, 215 km long, 64.5 N, 337 E. 11 P-31718 "Turtle-Back" fractured dome in Freyja Montes, 70 km wide, 72 N, 342 E. 12 P-37139 Lakshmi Planum/Clotho Tessera, 250 km wide, 61 N, 341 E. 13 P-37140 Cleopatra impact crater, 100 km diameter, 66 N, 10 E. 14 P-31741 W. region of Maxwell Montes & Lakshmi Planum, 300 km wide, 65 N, 357 E. 15 P-37236 Fractures and lava-flooded crater, 300 km wide, 60 S, 352 E. 16 P-37264 Sinuous volcanic channel N of Freyja Montes, 77 km wide, 76.5 N, 335 E. 17 P-37296 Dark halo impact crater in Lavinia, 38 km diameter, 2 km high, 21 N, 352 E. 18 P-37342 False-color image of volcano Sif Mons, 300 km diameter, 2 km high, 21 N, 352 E. 19 P-37375 Mosais of 3 impact craters and fractured plains in Lavinia Planitia, 500 km wide, 27 S, 339 E. 20 P-37431 False-color perspective of SE rim of Lakshmi Planum, Danu Montes rises 1.5 km above plateau (upper center). Page 23. CASSINI/HUYGENS - JPL19_: 1 The Saturn System (P-23209C/BW): This montage of images of the Satrunian system was prepared from an assemblage of images taken by the Voyager 1 spacecraft during its Saturn encounter November 1980. This artist's arrangement shows Dione in the forefront, Saturn rising behind, Tethys and Mimas fading in the distance to the right, Enceladus and Rhea off Saturn's rings to the left, and Titan in its distant orbit at the top. 2 Science Objectives for Cassini/Huygens (P-30821): The objectives can be broken up into five scientific categories, as shown, and include Magnetosphere, Saturn, Rings, Titan and Icy Satellites. 3 Cassini Interplanetary Trajectory: Depicts the planned Cassini Interplanetary Trajectory beginning with launch from Earth on 26 November 1995, followed by gravity assist flybys of Venus (2 December 1996), Earth (5 July 1998) and Jupiter (4 April 2000). A close flyby of the asteroid Clarissa occurs on 18 November 1998. Saturn arrival is scheduled for 25 June 2004, beginning of a four year orbital tour of the Saturn system. 4 Cassini Saturn Arrival and Initial Orbit: This schematic illustrates Cassini Saturn arrival and initial orbit. The Cassini spacecraft enters the Saturn system and performs an orbit insertion burn on 25 June 2004 to slow the spacecraft, put it into orbit around Saturn and start the four year orbital mission. A periapse raise maneuver is performed on 2 September 2004 to increase the minimum orbital distance and avoid Saturn's rings. They Huygens probe is released on 20 Oct. 2004 and the spacecraft performs an orbiter deflection maneuver 2 11/14/80. 5 Titan (P-23108 C): A thick haze layer is shown in this enhanced Voyager 1 image taken November 12, 1980 at a distance of 435,000 kilometers (270,000 miles). Voyager images of Saturn's largest moon show Titan completely enveloped by haze that merges with a darker "hood" or cloud layer over the north pole. Such a mantle is not present at the south pole. At Voyager's closest approach on Nov. 11, 1980, instruments found that this moon has a sub- stantial atmosphere, far denser than Mars' and possibly Earth's. 6 Entry! (P-38119): Artist's conception of Cassini Orbiter with the Huygens Probe entering Titan's atmosphere. 7 Huygens Descent Profile: This picture illustrates the Huygens Probe descent profile, beginning with the initial encounter with the Titan atmosphere and subsequent deceleration. As the probe slows a small parachute is released which deploys the main probe parachute. Once the parachute is fully open the decelerator shield is jettisoned and the probe drifts toward Titan's liquid or solid surface. About 40 km above the surface the parachute is jettisoned and the probe falls freely the remaining distance. Science data are continuously being transmitted by the probe to the orbiter for relay to earth. On impact, a small science package is released and a few minutes of post-impact science data are transmitted to the orbiter. Page 24. 8 Titan Radar (P-34839): This artist's conception illustrates the radar's capability to map the surface of Titan. Radar images of the surface are taken at a typical resolution of about 500 m. Altimetry and subsurface sounding measurements are made also. 9 Cassini Orbital Tour: This schematic depicts the first 36 orbits of the four year Saturn orbital tour. These orbits lie primarily in the equatorial plane of Saturn and contain close flybys of many of Saturn's ice satellites. The final orbits will place the spacecraft in a highly inclined orbit about Saturn's pole and provide excellent ring viewing and observations of Saturn and its magnetosphere at high latitudes. 10 Hyperion (P-23936 C/BW): Voyager 2 obtained this closeup view of Saturn's satellite Hyperion on August 24 from about 500,000 km. (300,000 miles). This photo was compiled from three separate images taken through violet, clear and green filters. It shows Hyperion to be an irregular, disc-shaped body. Its longest dimension is 360 km. (225 mi.), but in this view it presents a face measuring 325 km. by 250 km. (200 mi. by 150 mi.). The irregular shape is probably a result of repeated impacts that have taken off large pieces of the satellite. The large indentation at the bottom limb is one such crater; it is about 100 km (60 mi) across. The numerous small pits are impact craters, the smallest is about 10-20 km (6-12 mi.) across. 11 Enceladus (P-23955 C/BW): This Voyager 2 mosaic of Enceladus was made from images taken through the clear, violet and green filters August 25 from a distance of 119,000 kilometers (74,000 miles). In many ways, the surface of this satellite of Saturn resembles that of Jupiter's Galilean satellite Ganymede. Enceladus, however, is only one-tenth Ganymede's size. Some regions of Enceladus show impact craters up to 35 km. (22 mi.) in diameter, whereas other areas are smooth and uncratered. Linear sets of grooves tens of kilometers long traverse the surface and are probably faults resulting from deformation of the crust. The uncratered regions are geologically young and suggest that Enceladus has experienced a period of relatively recent internal melting. The rims of several craters near the lower center of the picture have been flooded by the smooth terrain. The satellite is about 500 km. (310 mi.) in diameter and has the brightest and whitest surface of any of Saturn's satellites. Features as small as 2 km. (1.2 mi.) are visible in this highest-resolution view of Enceladus. 12 Far encounter from Voyager shows a "classical" image of Saturn. 13 Saturnian Clouds #1 (P-23062 C/BW): This enhanced color image of the northern hemisphere of Saturn taken by NASA's Voyager 1 on November 5, 1980 at a range of 9 million kilometers (5.5 million miles) shows a variety of features in Saturn's clouds: Small-scale convective cloud features are visible in the brown belt; an isolated convective cloud with a dark ring is seen in the light brown zone; and a longitudinal wave is visible in the light blue region. The smallest features visible in this photograph are 175 kilometers (108.7 mi.) across. Page 25. 14 Saturnian Clouds #2 (P-23922C): This false color picture of Saturn's northern hemisphere was assembled from ultraviolet, violet and green images obtained August 19 by Voyager 2 from a range of 7.1 million kilometers (4.4 million miles). The several weather patterns evident include three spots flowing westward about 15-meters-per-second (33 mph). Although the cloud system associated with the western-most spot is part of this flow, the spot itself moves eastward at about 30 meters- per-second (65 mph). Their joint flow shows the anti-cyclonic rotation of the spot, which is about 3,000 km (1,900 mi.) in diameter. The ribbon-like feature to the north marks a high- speed jet where wind speeds approach 150 meters/sec. (330 mph). 15 Colors of Saturn's Rings (P-23953C): Possible variations in chemical composition from one part of Saturn's ring system to another are visible in this Voyager 2 picture as subtle color variations that can be recorded with special computer-processing techniques. This highly enhanced color view was assembled from clear, orange and ultraviolet frames obtained August 17 from a distance of 8.9 million kilometers (5.5 million miles). In addition to the previously known blue color of the C-ring and the Cassini Division, the picture shows additional color differences between the inner B-ring and outer region (where the spokes form) and between these and the A-ring. 16 Ring Spokes (P-23925 B/W): Voyager 2 obtained this high- resolution picture of Saturn's rings August 22, when the spacecraft was 4 million kilometers (2.5 million miles) away. Evident here are the numerous "spoke" features in the B-ring; their sharp, narrow appearance suggests short formation times. Scientists think electromagnetic forces are responsible in some way for these features, but no detailed theory has been worked out. Such pictures and analyses of Voyager 2's spoke movies may reveal more clues about the origins of these complex structures. 17 "Braided Ring" (P-23099 B/W): Saturn's F, or outermost ring was photographed from the un-illuminated face of the rings by Voyager 1 at a range of 750,000 kilometers (470,000 mi.). Complex structure is evident, with several components seen. Two narrow, braided, bright rings that race distinct orbits are evident. Visible is a broader, very diffuse component about 35 km. (20 mi.) in width. Also seen are "knots," which probably are local clumps of ring material, but may be mini-moons. 18 Cassini Spacecraft (with Huygens Probe detached): The remote sensing instrument platform is on a boom in the foreground, complete with its irregularly spaced sun shade. The long, narrow plasma wave antennas are shown attached to the magnetometer boom. The rotating turntable is shown on a boom extending away from the craft, along with its curved sun shade. 19 Cassini Spacecraft (view from direction opposite of Slide #18). 20 Comparison of Voyager, Galileo and Cassini Spacecraft: Schematics of the Voyager, Galileo and CRAF/Cassini are shown. CRAF/Cassini is the largest of the three and, to date, will be the largest spacecraft sent to the outer solar system.